NOTE: This article is not a substitute for sound medical advice. Please consult your primary care provider for the best plan that will work for you.
With health problems related to a high-fat diet garnering most of the spotlight when it comes to nutrition, it can seem weird to be told that there are fatty acids that we have to have in order to stay healthy. However, omega fatty acids are essential compounds, which humans cannot synthesize ourselves. Instead, we have to ingest them as part of a healthy diet.
While there are a range of fatty acids with varying structures and functions, there are two of primary importance to health that are referred to as ‘essential fatty acids’. These are the omega fatty acids alpha-linolenic acid (omega-3) and linolenic acid (omega-6).  Both are involved in the regulation of the cardiovascular and immune systems.
Most people are familiar with omega-3 from taking cod liver oil / fish oil (or witnessing other people’s grimaces when they did). Happily, these essential compounds are found in a range of food types that can easily be incorporated into most diets.
What Are Omegas Good For?
The list of health benefits of consuming omega fatty acids, particularly omega-3, is long and well-known, as well as the medical support for these claims. For example, reviews have claimed that there is little to no evidence to suggest omega-3 prevents cancer.
Aside from that, there are indicators that reveal that a strong intake of omegas can and will have far-reaching benefits such as:
- Lowering Blood Pressure. Omega-3 fatty acids reduce blood triglyceride (fat) levels and stimulate blood circulation.
- Improving Rheumatoid Arthritis. There is preliminary evidence that omega-3 from fish oil may reduce symptoms such as joint swelling.
- Improved Mental Health. Omega-3 fatty acids are thought to have a positive effect on depressive symptoms in those with bipolar disorder.
Omega 6 To 3 Ratios: The Delicate Balancing Act
The “ideal ratio” of omega-6 to omega-3 intake is 2:1 and it has been suggested that in “hunter-gatherer” days it was 1:1. Unfortunately, modern diets tend to include far more omega-6 relative to omega-3. A lower estimate of the typical ratio is 15:1.  This may not sound like a problem at first – but there is evidence to suggest that having a skewed ratio of the two essential omega fatty acids can negate the beneficial effects of both, even leading to new health problems.  The two are metabolised by the same enzymes, so if there is a flood of omega-6 in the body, omega-3 may not be available to the body in the required levels, even if sufficient quantities are consumed.
A 2002 scientific study reported that a ratio of 2.5:1 reduced rectal cell proliferation in patients with colorectal cancer, whereas a ratio of 4:1 with the same amount of omega-3 had no effect. 
The food with the highest amount of omega 3 compared to omega 6 is krill oil, with 1:12 – which will offer a superb “counterbalance” as supplementation to our diet that is too high in omega 6.
The worst? Corn oil is listed as having 46:1 Omega-6 to omega-3.
Major dietary sources of omega-3:
- Fish (particularly sardines and mackerel)
2. Soy beans
Major dietary sources of omega-6:
Most people are aware of 3 and 6, but chances are that you’ve never heard of a new category of omega-7 fats, which includes palmitoleic acid (found in macadamia nuts, sea buckthorn and some other natural sources. Omega-7 has been found by researchers to protect against metabolic syndrome.  However omega-7 sources often contain higher levels of less beneficial fats which may even be harmful – so it is suggested to supplement with a purified omega-7.
Omega 9’s are also not as discussed as 3’s and 6’s. The 9’s are considered “non essential” to get from your diet – however some of the Omega 9’s (but not all) are considered valuable for health. In particular: Oleic acid (found in olive oil, poultry fat, lard and macadamia oil), may have health benefits. Nervonic acid (found in salmon, nuts and seeds) maybe beneficial for brain function. 
Of course, the main thing when making any decisions regarding your health and diet is to consider your needs and other factors. If you have an existing medical condition, it is always best to check with your primary healthcare provider whether supplements or changes to your diet are safe, even with regards to essential nutrients.
1] E. Whitney and S. Rolfes (2008) Understanding Nutrition (11th ed.). https://www.amazon.ca/Understanding-Nutrition-Eleanor-Noss-Whitney/dp/0495116696
 C. MacLean et. al., “Effects of omega-3 fatty acids on cancer risk: a systematic review.” JAMA: the Journal of the American Medical Association, 2006. http://www.ncbi.nlm.nih.gov/pubmed/16434631
 P. Miller, M. Van Elswyk and D. Alexander, “Long-chain omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid and blood pressure: a meta-analysis of randomized controlled trials.” American Journal of Hypertension, 2014. http://www.ncbi.nlm.nih.gov/pubmed/24610882
 Rheumatoid Arthritis: In Depth (NCCIH): https://nccih.nih.gov/health/RA/getthefacts.htm
 P. Montgomery and A. Richardson, “Omega-3 fatty acids for bipolar disorder.” Cochrane database of systematic reviews (Online), 2008. http://www.ncbi.nlm.nih.gov/pubmed/18425912
 A. Simopoulos, “The importance of the ratio of omega-6/omega-3 essential fatty acids.” Biomed Pharmacother, 2002. http://www.ncbi.nlm.nih.gov/pubmed/12442909
 The importance of the ratio of omega-6/omega-3 essential fatty acids. (Biomed. Pharmacother. 2002). http://www.ncbi.nlm.nih.gov/pubmed/12442909
 Omega-7 Protects Against Metabolic Syndrome. http://www.lifeextension.com/Magazine/2014/4/Omega-7-Protects-Against-Metabolic-Syndrome/Page-01
 PaleoLeap – Omega 9 Fats. http://paleoleap.com/omega-9-fats/